```clj
(defn anonymous-component-example-var-bound-child [text]
  (js/console.log "RENDER" text)
  [:div text])

(defn anonymous-component-example []
  (let [*state (reagent/atom 0)]
    (js/console.log "CREATE parent")
    (fn []
      (js/console.log "RENDER parent")
      (let [state @*state]
        [:div.parent

         ;; var-bound component doesn't re-rendered when argument doesn't changed
         [anonymous-component-example-var-bound-child "var-bound child"]

         ;; changing key forces re-rendering of var-bound component even when argument doesn't changed
         ^{:key state}
         [anonymous-component-example-var-bound-child "var-bound child with changing key"]

         ;; anonymous component re-rendered even when argument doesn't changed
         [(fn [text]
            (js/console.log "RENDER anonymous child")
            [:div text])
          "anonymous child"]

         ;; constant key can't prevent re-rendering of anonymous component
         ^{:key "foo"}
         [(fn [text]
            (js/console.log "RENDER anonymous child with constant key")
            [:div text])
          "anonymous child with constant key"]

         [:br]
         [:div "State:" state]
         [:button
          {:on-click
           (fn [_]
             (js/console.log "-- clicked --")
             (swap! *state inc))}
          "Click me!"]]))))
```
Devtools console output after clicking button three times
```
CREATE parent
RENDER parent
RENDER var-bound child
RENDER var-bound child with changing key
RENDER anonymous child
RENDER anonymous child with constant key
-- clicked --
RENDER parent
RENDER var-bound child with changing key
RENDER anonymous child
RENDER anonymous child with constant key
-- clicked --
RENDER parent
RENDER var-bound child with changing key
RENDER anonymous child
RENDER anonymous child with constant key
-- clicked --
RENDER parent
RENDER var-bound child with changing key
RENDER anonymous child
RENDER anonymous child with constant key
```